Tetractenion luteum Seyrig, 1935

Berry, Terry Reynolds & Noort, Simon van, 2020, Revision of the endemic Afrotropical genus Tetractenion (Hymenoptera, Ichneumonidae) with an identification key to genera of Banchinae for the region, ZooKeys 1007, pp. 49-84 : 49

Tetractenion luteum Seyrig, 1935 Fig. 3

Type material.

Holotype ♂: Nyeri, Kenya, June 1932 (MNHN). Paratype ♀: Elizabethville, Democratic Republic of Congo, 4 January 1921, M. Bequaert, Det. PLG Benoit, 1952 (RMCA). Additional material. ♀: South Africa, Eastern Cape, Pearston, Plains of Camdeboo Game Reserve, 32°32.033'S, 25°14.267'E, 969 m, 30.x.2009-22.ii.2010, S. van Noort, Malaise Trap, Camdeboo Escarpment Thicket, PCD09-ACA1-M02, SAM-HYM-P047483 (SAMC). ♂, ♀: South Africa, Eastern Cape, Asante Sana Game Reserve, 32°16.762'S, 24°57.309'E, 1186 m, 6.x.2010-17.i.2011, S. van Noort, Malaise Trap, Southern Karoo Riviere Riverine Woodland, ASA09-WOO1-M18, SAM-HYM-P047487 (SAMC, NHMUK). ♂: South Africa, Eastern Cape, Asante Sana Game Reserve, 32°16.762'S, 24°57.309'E, 1186 m, 7 Apr-28 July 2010, S. van Noort, Malaise Trap, Southern Karoo Riviere Riverine Woodland, ASA09-WOO1-M10, SAM-HYM-P047484 (SAMC). ♂: South Africa, Eastern Cape, Asante Sana Game Reserve, 32°15.841'S, 24°57.091'E, 1354 m, 6.x.2010-17.i.2011, S. van Noort, Malaise Trap, Camdeboo Escarpment Thicket, ASA09-BUS1-M17, SAM-HYM-P047485 (SAMC). Namibia, near Windhoek: a bush between kleine Kuppe and Aus Born Mountains, A. Gumovsky, 23-25.xii.2011, SAM-HYM-P047488 (SAMC). ♂: Exetastes sp. indet. In B.M. G.J. Kerrich det. 1958. Pres by Com Inst Ent BM 1960-3. U.C. [Nigeria], Ibadan, 9.9.1953, Coll. G.H. Caswell, P49 (NHMUK).

Differential diagnosis.

Tetractenion luteum is immediately distinguishable from the other species in the genus as this species is the only yellow-colored Tetractenion species to possess simple hind tarsal claws, and this character is consistent in both sexes. The head is rounded behind the eyes, distinguishing the species from T. acaule and T. pascali . The malar space nearly as long as the width of the base of the mandible separates T. luteum from T. acaule , T. pseudolutea , and T. ibayaensis . The pronotal collar is weakly wrinkled, separating the species from T. acaule and T. rosei . Metasomal tergite II is longer than wide and distinguishes the species from T. ibayaensis ; and a quadrate tergite III separates T. luteum from T. pseudolutea , T. pascali , and T. rosei . Furthermore, T. pascali is the only other species that possess dense microtrichia on the wings.

Description

(updated from Seyrig 1935). Size 7.6-10.4 mm. Color: head yellow with black marking on occiput to middle of frons, no contact with eyes on vertex; meso- and metasoma, fore and mid legs uniformly yellow, hind leg mostly yellow with shades of infuscation on tibia and tarsus infuscate; wings with dense microtrichia, venation brown, pterostigma yellow.

Head with temple short, rounded behind eyes; occiput deeply and angularly excavated, occipital carina strong, extending to lower gena at base of mandible; eyes very large, malar space a bit shorter than width of mandibular base; face and clypeus finely, evenly and rather sparsely punctate on a matt background; face with three lobes, tentorial pits deep; clypeus small, laterally convex with declivity, apically invaginated, with clypeus edge convex; mandibular teeth triangular, lower tooth longer than upper tooth; antenna about as long as body, slender and apically tapered.

Mesosoma stout, matt to sub-polished; pronotum finely punctate on a sub-polished background, no more than a wrinkle present on pronotal collar; mesoscutum moderately punctate, mesoscutal lobes hardly present, notauli posteriorly meeting before reaching the scutellum; mesonotum and mesopleuron finely punctate; mesopleuron higher than wide, epicnemial carina ending at anterior edge of mesopleuron; shallow pits on mesopleuron and propodeum; propodeum weakly convex, matt to sub-polished, moderately punctate posteriorly confluently grading into transverse wrinkles, posterior transverse carina reduced, lateral longitudinal carinae present but faint, spiracle small and circular-elliptical.

Metasoma with a sub-polished background, anterior half of tergite I and dorso-lateral region of tergite II hardly punctate, indistinctly punctate beyond base; tergite I twice as long as wide, glymma present, tapered anteriorly, weak to indistinctly dorso-ventrally depressed in the medial region, spiracle positioned in front of middle and protruding, especially dorsally; tergite II longer than wide, gastrocoeli indistinct; tergite III quadrate.

Fore wing with ramellus absent on Rs-M vein; areolet large and quadrate with a short stalk receiving 2m-cu at center. Hind wing with Cu1 shorter than cu-a such that Cu2 arises above the middle of these combined veins. Legs very long; hind femur reaching beyond metasomal apex, length of tibia III plus tarsus III as long as body, spurs of tibia III longer than half metatarsal length; fore and mid tarsal claws pectinate, hind tarsal claws simple.

Distribution.

Democratic Republic of Congo, Kenya, Namibia, Nigeria, and South Africa.

Figures

Figure 3. Tetractenion luteum Holotype (MNHN) A habitus, lateral view B habitus, dorsal view C head, anterior view D data labels. Photographs of holotype RECOLNAT (ANR- 11 - INBS- 0004) - Christophe Herve - 2014. http: // coldb. mnhn. fr / catalognumber / mnhn / ey / ey 9334 (used with permission of Agniele Touret-Alby - Curator of Hymenoptera MNHN).